1. Field of the Invention
This invention relates to a recording method of recording medium and more particularly, relates to a recording method for recording digital signals supplied with an additional information to a recording medium.
2. Description of the Related Art
There are magneto-optical discs as data rewritable recording mediums of disc type which can record digital data such as computer data. While data is recorded in the magneto-optical disc, a recording film of the magneto-optical disc is heated on one side of the magneto-optical disc to a temperature higher than the Curie point by a light beam emitted from an optical pickup, and at the same time, a vertical magnetic field is supplied to the heated area on the other side of the magneto-optical disc by a magnetic head. As a result, digital data is recorded by magnetizing the recording film of the magneto-optical disc in accordance with the polarity of the vertical magnetic field.
The magneto-optical disc is proposed in which analog signals such like sound signals or music information are first digitalized to be recorded. A magneto-optical disc recording/reproducing unit using the magneto-optical disc records the digitalized audio data on the magneto-optical disc in predetermined block units. The audio data is recorded in block units so as to be recorded discretely on the magneto-optical disc.
In this magneto-optical disc recording/reproducing unit, audio data to be recorded is sequentially inputted into an volume compressor, in which the audio data thus input is divided into blocks at a predetermined cycle in order to process a volume compression on each block. Such blocks of volume-compressed audio data are hereinafter referred to as sound groups.
A sound group of audio data forms two sectors with eleven continuous blocks and further one cluster with thirty six sectors. Therefore, the recording/reproducing unit records or reproduces the compressed audio data in cluster units based on the sectors
As shown in a table of FIG. 1, in the magneto-optical disc unit, twenty three hundred and fifty two bytes of data are assigned to each sector, the area represented by longitudinal byte addresses "0" to "3" out of which are allocated to the header of the each sector.
The twelve-byte area represented by longitudinal addresses "0" to "2" is allocated to a synchronization pattern (sync), whereto a formatted synchronization pattern is assigned, and the address of a cluster is allocated to the first and second bytes of the longitudinal address "3".
The respective sectors are continuously formed on a magneto-optical disc every thirty six sectors which are grouped into clusters as addresses for the management of which fourteen-bit addresses are assigned.
The sector address is also assigned following the address of each clusters and the mode data of the magneto-optical disc follows the cluster address.
Furthermore, a main data area of twenty three hundred and thirty six bytes are formed following this header address, to which a user's desired data is assigned.
As shown in FIG. 2, in the magneto-optical disc, data "02h" is recorded as mode data, "00h" of four bytes following a header is recorded subsequently thereof, and audio data is recorded subsequently thereof.
To each sector thus formed is assigned a sound group as shown in FIG. 3.
That is, in an even numbered address sector, the main data area following data "00h" at longitudinal address "4" corresponding to the table shown in FIG. 1 is divided at intervals of longitudinal address "105" into sub-areas which are respectively assigned sequential sound groups of data.
The area at longitudinal address "53" remaining as a result of the above division of the main data area is assigned to the sixth sound group 5, and the area beginning at longitudinal address "5" of a subsequent odd address sector is recorded with the remaining data of the sixth sound group 5.
For this odd address sector in the magneto-optical disc, the remaining area is further divided at intervals of longitudinal address "105" into sub-areas which are respectively assigned the remaining sound groups.
Therefore, in the recording/reproducing unit using a magneto-optical disc of this type, sound groups are formed by processing a volume compression on sequentially input audio data. The sound groups thus formed into sectors are further formed into a cluster, as the unit of which audio data can be recorded in the magneto-optical disc.
In the case where audio data is thus recorded on the magneto-optical disc in cluster units, track-jumped clusters can be re-recorded, for example, even when a track-jump occurs because of vibration during a recording operation, by using a mass storage memory circuit as a buffer storage. As a result, continuous audio data can be recorded on a magneto-optical disc without a drop out.
A recording area for recording management data of audio data is formed as a management area on the inner periphery of the magneto-optical disc, whereas a data recording area for recording data of this cluster is formed on the outer area of this management control area.
Therefore, the audio data is sequentially recorded in cluster units into this data recording area.
In contrast, the management data recorded on the management area is used to reproduce desired data out of audio data recorded in cluster on the data recording area.
That is, this management data is defined as data in sector units similar to main data, so that the management data can be standardized with regard to the first to fourth sectors.
The third to fifth sectors "2" to "4" out of the second to fifth sectors "1" to "4" are used for options. As shown in FIG. 4, a cluster address is assigned after a header and subsequently data "00h" is recorded in the first sector, i.e., sector "0".
Moreover, after a predetermined code data (Maker code and Mode 1 code) is assigned in the first sector, other data (First TNO and Last TNO) indicating the recording start position and recording end position of the main data is assigned.
At longitudinal address "11" of this first sector, 2-byte disc identification data can be recorded. The first sector is subsequently assigned a pointer (P-DFA) indicating the position of a defective area in the data recording area and another pointer (P-EMPTY) indicating the initial position of an unrecorded area in the data recording area. Furthermore, at subsequent longitudinal address "12", the first sector is assigned a pointer (P-FRA) indicating the initial position of the main data recorded in the data recording area and subsequently pointers (P-TNO1, . . . , P-TNO255) indicating the recording start positions of respective data items.
Thus, a magneto-optical disc recording/reproducing unit for the record and reproduction of audio signals is enabled to detect the initial positions of recorded music with the aid of these pointers (P-FRA, PTNO1, . . . , P-TNO255).
In each area at longitudinal address "76" or less, a start address and an end address are recorded to indicate the recording start position and recording end position, respectively, of the main data, and in pointers (P-FRA, P-TNO1, . . . , P-TNO255), the recording positions of these start addresses are pointed.
Thus, the magneto-optical disc recording/reproducing unit is enabled to detect a recording position regarding musical composition designated by the user through locating the start address and end address pointed to by the pointers.
As shown in FIG. 5, at these start address and end address, the address of a cluster is recorded in 14 bits, the address of a sector is recorded in 6 bits, and the address of a sound group is recorded in 4 bits, whereupon the magneto-optical disc recording/reproducing unit is enabled to perform such processes as locating a musical composition by using the units "cluster," "sector," and "sound group," with regard to audio data recorded in cluster units.
In addition, a small recording area on the data recording area designated by such a set of start and end addresses is referred as a part P.
Moreover, in this management data, mode data (Track mode) indicating the processing mode of each part is recorded after this start address. Copy inhibit data, write inhibit data, audio data, stereo data, monaural data, etc. can be distinguished by this mode data, and furthermore it can be recognized by the mode data that whether or not an emphasis process has been performed.
In contrast, in an end address, a link pointer (Link-P) is subsequently recorded to indicate the connection of a part P. The link pointer (Link-P) can designate the recording position of a start address corresponding to this end address.
As shown in FIG. 6A, when an empty magneto-optical disc is recorded with audio data for the first time, the audio data is recorded on the data recording area of the magneto-optical disc in a manner such that the renditions of sequential musical compositions 1, 2, etc., follow each other in succession.
In this case, the respective audio data are recorded on the magneto-optical disc in every part P1, P2, P3, etc., each of which is defined by a set of beginning and ending addresses.
By contrast, when a musical performance of a long musical composition 5 is recorded after the erasure of musical compositions 2 and 4, as shown in FIG. 6B, continuous audio data about this musical composition 5 is divided so as to be recorded in the second part P2 and the fourth part P4.
In such a case, when the start address of the musical composition 5 is specified with a pointer, the performance start position of the second part P2 is detected by the start address, and furthermore, the recording end position of part P2 is detected by an end address forming a pair with the start address.
Moreover, in the magneto-optical disc, a start address is detected when a link pointer (Link-P) following this end address is specified similarly to the pointers (P-FRA, P-TNO1, . . . , P-TNO255) of the fourth part P4. Thus, the magneto-optical disc can record audio data by the effective use of the data recording area of the magneto-optical disc by rewriting this management area data every time when a recording or an erasing operation is repeated.
The pointers (P-FRA, P-TNO1, . . . , P-TNO255) are formed in correspondence to the respective audio data recorded on the magneto-optical disc, and the corresponding parts P are specified respectively together with link pointers.
In contrast, when the musical composition 2 has been erased from the audio data recorded continuously, the magneto-optical disc recording/reproducing unit designates the erased area with a pointer (P-EMPTY) pointing to the initial position of an unrecorded area in the data recording area.
The pointer (P-EMPTY), similar to the other pointers (P-FRA, P-TNO1, . . . , P-TNO255), is designed so as to designate the start address of a corresponding part P, whereby the magneto-optical disc recording/reproducing unit replaces the designation of parts P2 and P4 previously pointed to by pointers (PTNO1, P-TNO2, . . . ) with the designation of a pointer (P-EMPTY) pointing to the initial position of the unrecorded area and the link pointer (Link-P) of an end address forming a pair with the start address pointed to by this pointer. Thus, audio data can be erased from the magneto-optical disc easily.
Thus, in the magneto-optical disc unit, the audio data between clusters designated by the start address and end address is reproduced in cluster units. Thereafter, the audio data, which is designated by a sound group address corresponding to a start address and an end address, is reproduced by processing the data in sector units. Therefore, the audio data recorded discretely on a magneto-optical disc can be reproduced easily.
At this time, in the magneto-optical disc recording/reproducing unit, the audio data is recorded in cluster units as described above and the audio data is reproduced in cluster units. This prevents the reproducing sounds from "skipping" due to reproducing track-jumped clusters, if any, by using a mass storage memory circuit as buffer storage.
In this connection, of the remaining management data sectors, in the second sector, sector 1, as shown in FIG. 7, a disc name and a track name are assigned in ASCII code in correspondence to a start address and an end address after a header and pointers (P-TNA1, PTNA2, . . . ) are recorded similarly to the first sector (i.e. sector 0).
By contrast, in the third sector of the management data, sector 2, as shown in FIG. 8, pointers (P-TRD1, P-TRD2, . . . ) are recorded in correspondence to the pointers (P-TNO1, P-TNO2, . . . ) of the first sector after a header, etc., are recorded similarly to the first sector.
Therefore, in the third sector, sector 2, recording time (Track rec data and time), etc., can be record by pointers (P-TRD1, P-TRD2, . . . ), with regard to respective audio data corresponding to the pointers (P-TNO1, P-TNO2, . . . ) of the first sector.
Furthermore, in the fifth sector of the management data, sector 4, as shown in FIG. 9, pointers (P-TNA1, P-TNA2, . . . ) are formed similarly and a disc name and a track name can be recorded in Japanese kanji code.
Thus, such a magneto-optical disc recording/reproducing unit is connected to some audio equipment, such as an analog tape player, LP record player, or compact disc player, as a source of audio information. The analog audio signal output from these audio equipment is converted into a digital audio signal, and audio data is recorded. Otherwise, the magneto-optical disc recording/reproducing unit is connected to some digital audio equipment, such as a compact disc player, digital audio tape recorder, or magneto-optical disc recording/reproducing unit. The digital audio signal output from these digital audio equipment is recorded.
When audio signals supplied from various sources are recorded on the magneto-optical disc recording/reproducing unit described above, tracks are controlled by automatically giving track numbers (musical composition number), which are also given in musical units in a compact disc, for example, for the musical compositions recorded on the magneto-optical disc. To perform such track number control, it is necessary to detect changing of musical compositions with respect to the analog or digital audio signals supplied.
Especially in cases where digital data of input signals are supplied from, for example, a compact disc player, their sub-code data is also sent at the same time with digital data. Therefore, if the track number information of sub-code data is fetched as it is, the track number control and updating numbers with respect to the musical compositions recorded in the magneto-optical disc can be easily performed.
However, there are proper cases where a user reproduces a desired track by searching for musical compositions which are recorded in a disc of a compact disc player, for example, that is, a search operation (access operation) for performing program reproduction so as to play musical compositions in a desired order is carried out during the reproducing operation. In this case, the excessive change of the sub-code data occurs due to the extraction of the sub-code data of another track in access or the detection of incorrect data. At this time, in the magneto-optical disc recording/reproducing unit, a problem occurs that wrong track numbers are given to the recorded musical compositions because track numbers are updated in accordance with the track number information in the sub-code data on the recording apparatus side.
As described above, in compact disc players, for example, the programmed reproduction mode is set so that musical compositions recorded in a compact disc can be reproduced in a user's desired order.
Accordingly, a magneto-optical disc recording/reproducing unit is enabled to record audio data in the magneto-optical disc in a user's desired order dispensing with the otherwise necessary recording/reproducing operations for each end of reproduction of musical compositions, by connecting to a piece of audio equipment set in its programmed reproduction mode and being put in its recording mode. That is, if once a piece of audio equipment and a magneto-optical disc recording/reproducing unit are connected and the reproducing or recording operation is set, it is possible to omit the otherwise necessary operations to be carried out until the end of recording. This recording method is hereinafter referred as automatic recording.
However, there may be some compact discs which have been recorded with only enough music data for a musical performance time of some thirty minutes.
Accordingly, if a magneto-optical disc capable of recording for, for example, sixty minutes is loaded onto a magneto-optical disc recording/reproducing unit, and audio data to be reproduced from this compact disc is automatically recorded, a mute will record for no less than thirty minutes in the magneto-optical disc after the musical performance on the part of the compact disc player terminates.
To prevent from recording this mute to the magneto-optical disc, the user needs to perform a stop operation on the magneto-optical disc unit when the reproduction of a compact disc terminates. As a result, even in this automatic recording mode a user's manipulation is actually required, so that there are some problems to be solved for practical use.